Smartphone users might balk at letting a random app like Candy Crush or Shazam track their every move via GPS. But researchers have found that Android phones reveal information about your location to every app on your device through a different, unlikely data leak: the phone’s power consumption.

Researchers at Stanford University and Israel’s defense research group Rafael have created a technique they call PowerSpy, which they say can gather information about an Android phone’s geolocation merely by tracking its power use over time.